Add nested posts UI (#5)

## Summary
- Cut hunt, question, submission, voting, hiding, and profile flows over to unified posts
- Render nested replies with permission-aware inline Reply/Edit controls and edited markers
- Add post profile queries and the author index migration they depend on

Co-authored-by: codegirl-007 <s.raide@gmail.com>

internal/store/post.go

@@ -258,6 +258,39 @@ func GetPostThread(ctx context.Context, db *sql.DB, rootID string) (*Post, error
 	return buildPostTree(posts, rootID)
 }
 
+// GetPostThreadForViewer includes root voting and answered annotations.
+func GetPostThreadForViewer(
+	ctx context.Context,
+	db *sql.DB,
+	rootID string,
+	viewerID string,
+) (*Post, error) {
+	root, err := GetPostThread(ctx, db, rootID)
+	if err != nil {
+		return nil, err
+	}
+	summary, err := sqlc.New(db).GetRootPostVoteSummary(ctx, sqlc.GetRootPostVoteSummaryParams{
+		ViewerID: viewerID,
+		RootID:   rootID,
+	})
+	if err != nil {
+		return nil, err
+	}
+	root.Score = int(summary.Score)
+	root.UserVote = int(summary.UserVote)
+	root.Answered = postTreeContainsRole(root, RoleAdmin)
+	return root, nil
+}
+
+func postTreeContainsRole(post *Post, role Role) bool {
+	for _, reply := range post.Replies {
+		if reply.AuthorRole == role || postTreeContainsRole(reply, role) {
+			return true
+		}
+	}
+	return false
+}
+
 func buildPostTree(posts []Post, rootID string) (*Post, error) {
 	byID := make(map[string]*Post, len(posts))
 	for i := range posts {
@@ -334,6 +367,89 @@ func ListRootPosts(ctx context.Context, db *sql.DB, postDate, viewerID string) (
 	return posts, nil
 }
 
+// ListRootPostsByAuthor returns visible roots created by an author, newest first.
+func ListRootPostsByAuthor(ctx context.Context, db *sql.DB, authorID string) ([]Post, error) {
+	rows, err := sqlc.New(db).ListRootPostsByAuthor(ctx, sqlc.ListRootPostsByAuthorParams{
+		AuthorID:    authorID,
+		HiddenState: string(PostStateHidden),
+		RowLimit:    ProfileListLimit,
+	})
+	if err != nil {
+		return nil, err
+	}
+	posts := make([]Post, 0, len(rows))
+	for _, r := range rows {
+		posts = append(posts, postFromValues(
+			db,
+			r.ID,
+			r.ParentID,
+			r.AuthorID,
+			r.AuthorName,
+			r.AuthorRole,
+			r.Title,
+			r.Body,
+			r.City,
+			r.PostDate,
+			r.PostState,
+			r.CreatedAt,
+			r.UpdatedAt,
+		))
+	}
+	return posts, nil
+}
+
+// ListRootPostsAnsweredBy returns visible roots containing a reply by adminID.
+func ListRootPostsAnsweredBy(ctx context.Context, db *sql.DB, adminID string) ([]Post, error) {
+	rows, err := sqlc.New(db).ListRootPostsAnsweredBy(ctx, sqlc.ListRootPostsAnsweredByParams{
+		HiddenState: string(PostStateHidden),
+		AdminID:     adminID,
+		RowLimit:    ProfileListLimit,
+	})
+	if err != nil {
+		return nil, err
+	}
+	posts := make([]Post, 0, len(rows))
+	for _, r := range rows {
+		posts = append(posts, postFromValues(
+			db,
+			r.ID,
+			r.ParentID,
+			r.AuthorID,
+			r.AuthorName,
+			r.AuthorRole,
+			r.Title,
+			r.Body,
+			r.City,
+			r.PostDate,
+			r.PostState,
+			r.CreatedAt,
+			r.UpdatedAt,
+		))
+	}
+	return posts, nil
+}
+
+// SetRootPostState changes a root post's state.
+func SetRootPostState(ctx context.Context, db *sql.DB, id string, state PostState) error {
+	switch state {
+	case PostStateVisible, PostStateHidden, PostStateLocked:
+	default:
+		return fmt.Errorf("%w: invalid post state", ErrInvalidPost)
+	}
+	n, err := sqlc.New(db).UpdateRootPostState(ctx, sqlc.UpdateRootPostStateParams{
+		PostState: string(state),
+		UpdatedAt: time.Now().UTC().Format(time.RFC3339Nano),
+		ID:        id,
+	})
+	if err != nil {
+		return err
+	}
+	if n == 0 {
+		return sql.ErrNoRows
+	}
+	return nil
+}
+
 // SetPostVote sets value to 1, -1, or 0 on a visible root post.
 func SetPostVote(ctx context.Context, db *sql.DB, userID, postID string, value int) error {
 	if value != 1 && value != -1 && value != 0 {